Dynamic bladder outlet obstruction (BOO) was induced in adult male rhesus monkeys with a mean weight of 7.5kg by implanting a vascular occlusive cuff mated to a subcutaneous access port around the bladder neck. Varying degrees of obstruction were created by inducing increasing volumes of isotonic contrast. The amount of obstruction was quantified by the %_decrease in open area of the cuff for increasing volumes. Three levels of obstruction were induced corresponding with Grade I = 11.4%, Grade II = 43.6% and Grade III = 70%. Significant urodynamic changes in the bladder function were observed particularly with Qmax (3.8ml/sec in control versus 2.08 in BOO, p = 0.003), voiding time (40.8 sec in control versus 67.1 sec in BOO, p = 0.001), bladder capacity (144ml in control versus 224 in BOO, p = 0.026 and maximum voiding pressure (55.1cm H2O) in control versus 85.6cm H2O in BOO, p = 0.0451), bladder compliance was decreased only in severe BOO. Additionally, detrusor instability appeared in one monkey (25% of the animals), but no residual urine was collected from any of the obstructed monkeys. Also, there were no significant urodynamic changes between early and late grade-III obstruction. Significant changes of the bladder function could be anticipated by changing the grade (severity) of obstruction and not by the duration of the same grade. Our system can accurately determine the functional state of the detrusor, enhancing its c correlation